Insights into deactivation mechanism of Pd@CN catalyst in the liquid-phase hydrogenation of phenol to cyclohexanone

The deactivation mechanism of Pd@CN catalyst in the liquid-phase phenol hydrogenation was investigated by designing many experiments. The phenol conversion decreased by 40% through five reaction cycles. The catalyst deactivation could be mainly ascribed to the surface coverage and the pore blockage with organic matters including cyclohexanone and other derivatives. Three after-treatment methods, i.e., water washing, drying and storing in water, strongly affected the catalytic activity of Pd@CN. After the reaction, by storing the recovered Pd@CN catalyst in water, its catalytic performance could be maintained. These findings provide in-depth insights on the deactivation and recycling of Pd@CN catalyst.